1. Field of the Invention
The present invention relates to a method for producing a semiconductor optical device used for optical modulation and a semiconductor optical device.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2012-252290 discloses a semiconductor Mach-Zehnder modulator used for modulating optical signals.
The Mach-Zehnder modulator disclosed in Japanese Unexamined Patent Application Publication No. 2012-252290 includes an optical waveguide having a high-mesa structure. The optical waveguide includes an n-type InP cladding layer, a quantum well active layer, a p-type InP cladding layer, and a p-type contact layer stacked on an n-type InP substrate. The optical waveguide is covered with a resin. An electrode pad is disposed at a position away from the optical waveguide. The electrode pad is disposed on the resin. A metal interconnection that connects the optical waveguide and the electrode pad passes above another optical waveguide.